Conventionally, in a plant and a factory, a distributed control system (DCS) is established in order to implement advanced automatic operations. Field devices (a measurement device and an operation device) and a controller managing and controlling them are connected to each other via a communication means in the distributed control system. It is desirable that information is transmitted from the field device to the controller without losing the information and delaying, in order to stabilize operation of the plant and the factory.
For example, indices such as a packet error rate (PER), a received signal strength indication (RSSI), and a delay between transmission and reception (Latency), are used for monitoring and setting a communication route. A device which sets a wireless route based on these indices is provided.